This invention relates to a self-opening closure cap for bottles or other containers, more particularly to a closure cap having a hole at the central portion thereof and forming a self-opening means integrally formed with the seal placed under the cap and protruded therefrom through the hole.
In the prior art, a large number of bottles or other containers for carrying beverages such as beer, juice, or the like have been closed by a crown cap or a similar closure device which can generally only be properly removed by the use of a suitable tool, such as a mechanical opener. Similarly, where metal containers are used, mechanical devices are necessary to puncture the end of the can to remove its contents. In either circumstance, it is a great inconvenience to the user to attempt to open such a device when a mechanical device or opener is not at hand or is otherwise not operative or available.
In an attempt to solve these problems, a number of methods have been suggested in the prior art, such as those shown and described in the U.S. Pat. Nos. 1,127,357; 1,180,864; 2,426,101; 2,426,102 and 3,199,706. In the devices described in these patents, generally a pull ring or a tab is provided and integrally shaped with the cap for enabling one to exert a pulling force wherby the closure cap will be removed. In fact, the cap should be closed tightly to prevent leakage so that it can hardly be pulled off by finger. For this main reason, none of the caps described in the mentioned patents are useful.